[dotnet] Add C# 14 extension to polyfill ArgumentNullException.ThrowIfNull

[RenderMichael]

User description

This includes an internal language version bump, as well as some polyfill files. In exchange, we can use modern C# methods across all TFMs.

🔗 Related Issues

💥 What does this PR do?

🔧 Implementation Notes

💡 Additional Considerations

🔄 Types of changes

• Cleanup (formatting, renaming)

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PR Type

Enhancement

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Description

• Replace manual null-check patterns with ArgumentNullException.ThrowIfNull()

• Add C# 14 extension method polyfill for modern null validation

• Reduce boilerplate code across 30+ files in WebDriver codebase

• Maintain backward compatibility with older .NET target frameworks

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Diagram Walkthrough

flowchart LR
  A["Manual null checks<br/>if x is null throw"] -->|"Refactor to"| B["ArgumentNullException<br/>.ThrowIfNull()"]
  C["Polyfill files<br/>for older TFMs"] -->|"Enable"| B
  B -->|"Applied to"| D["30+ WebDriver files<br/>BiDi, DevTools, Drivers"]

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File Walkthrough

	Relevant files
Enhancement	2 files ArgumentNullExceptionExtensions.cs Add ThrowIfNull extension method polyfill                                +38/-0    CallerArgumentExpressionAttribute.cs Add CallerArgumentExpression attribute polyfill                    +29/-0
Cleanup	26 files PermissionsBiDiExtensions.cs Replace manual null check with ThrowIfNull                              +1/-4      WebDriver.Extensions.cs Replace manual null check with ThrowIfNull                              +1/-1      ChromiumDriver.cs Replace multiple manual null checks with ThrowIfNull          +2/-8      Cookie.cs Replace manual null check with ThrowIfNull                              +1/-4      CookieJar.cs Replace manual null checks with ThrowIfNull                            +2/-8      CommandResponseTypeMap.cs Replace multiple manual null checks with ThrowIfNull          +2/-8      WebSocketConnection.cs Replace manual null checks with ThrowIfNull                            +2/-8      V141Network.cs Replace multiple manual null checks with ThrowIfNull          +7/-28    V142Network.cs Replace multiple manual null checks with ThrowIfNull          +7/-28    V143Network.cs Replace multiple manual null checks with ThrowIfNull          +7/-28    DriverOptions.cs Replace manual null check with ThrowIfNull                              +1/-4      DriverProcessStartedEventArgs.cs Replace manual null check with ThrowIfNull                              +1/-4      FirefoxDriver.cs Replace multiple manual null checks with ThrowIfNull          +2/-8      FirefoxProfile.cs Replace manual null check with ThrowIfNull                              +1/-4      Preferences.cs Replace multiple manual null checks with ThrowIfNull          +4/-16    InternetExplorerDriver.cs Replace multiple manual null checks with ThrowIfNull          +2/-8      Actions.cs Replace manual null check with ThrowIfNull                              +1/-4      WheelInputDevice.cs Replace manual null check with ThrowIfNull                              +1/-4      LogContext.cs Replace manual null check with ThrowIfNull                              +1/-4      JavaScriptEngine.cs Replace multiple manual null checks with ThrowIfNull          +7/-28    Logs.cs Replace manual null check with ThrowIfNull                              +1/-4      HttpCommandExecutor.cs Replace manual null checks with ThrowIfNull                            +2/-8      RemoteWebDriver.cs Replace manual null check with ThrowIfNull                              +1/-4      SafariDriver.cs Replace multiple manual null checks with ThrowIfNull          +2/-8      TargetLocator.cs Replace manual null check with ThrowIfNull                              +1/-4      WebDriver.cs Replace multiple manual null checks with ThrowIfNull          +7/-28

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[qodo-code-review]

PR Compliance Guide 🔍

Below is a summary of compliance checks for this PR:

Security Compliance
⚪	Type extension conflict Description: The polyfill declares 'namespace System;' and uses a C# 14 'extension(ArgumentNullException)' type extension inside the System namespace, which risks type/namespace conflicts or ambiguous resolution with BCL types on supported TFMs and could lead to undefined behavior or runtime/type loading issues. ArgumentNullExceptionExtensions.cs [23-38] Referred Code namespace System; internal static class ArgumentNullExceptionExtensions { extension(ArgumentNullException) { public static void ThrowIfNull([NotNull] object? arg, [CallerArgumentExpression(nameof(arg))] string paramName = "") { if (arg is null) { throw new ArgumentNullException(paramName); } } } }
Ticket Compliance
🟡	🎫 #1234 🔴 Investigate and fix regression where clicking a link with JavaScript in href no longer triggers in Selenium 2.48.x on Firefox 42 (worked in 2.47.1). Provide verification that alerts are triggered as in prior version.
🟡	🎫 #5678 🔴 Diagnose and resolve "Error: ConnectFailure (Connection refused)" occurring when instantiating additional ChromeDriver instances on Ubuntu 16.04 with Chrome 65 and ChromeDriver 2.35 using Selenium 3.9.0. Ensure stable creation of multiple ChromeDriver instances without connection errors. Provide steps or fixes to avoid the error in subsequent instantiations.
Codebase Duplication Compliance
⚪	Codebase context is not defined Follow the guide to enable codebase context checks.
Custom Compliance
🟢	Generic: Meaningful Naming and Self-Documenting Code Objective: Ensure all identifiers clearly express their purpose and intent, making code self-documenting Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Robust Error Handling and Edge Case Management Objective: Ensure comprehensive error handling that provides meaningful context and graceful degradation Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Secure Error Handling Objective: To prevent the leakage of sensitive system information through error messages while providing sufficient detail for internal debugging. Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Secure Logging Practices Objective: To ensure logs are useful for debugging and auditing without exposing sensitive information like PII, PHI, or cardholder data. Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
	Generic: Security-First Input Validation and Data Handling Objective: Ensure all data inputs are validated, sanitized, and handled securely to prevent vulnerabilities Status: Passed Learn more about managing compliance generic rules or creating your own custom rules
⚪	Generic: Comprehensive Audit Trails Objective: To create a detailed and reliable record of critical system actions for security analysis and compliance. Status: Logging Detail: The new changes focus on null checks and a polyfill without introducing or modifying audit logging for critical actions, which may be outside this PR's scope but cannot be confirmed from the diff alone. Referred Code ArgumentNullException.ThrowIfNull(url); this.Log($"Opening connection to URL {url}", DevToolsSessionLogLevel.Trace); bool connected = false; DateTime timeout = DateTime.Now.Add(this.startupTimeout); Learn more about managing compliance generic rules or creating your own custom rules
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🟡 - Partial Compliant
🔴 - Not Compliant
⚪ - Requires Further Human Verification
🏷️ - Compliance label

[qodo-code-review]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
High-level	✅ Conditionally compile the ThrowIfNull polyfill Suggestion Impact: The polyfill files were effectively removed from compilation content; additionally, CallerArgumentExpressionAttribute.cs already includes a #if !NET8_0_OR_GREATER guard, aligning with the suggestion to conditionally compile polyfills for newer frameworks. code diff: # File: dotnet/src/webdriver/Internal/Polyfills/CallerArgumentExpressionAttribute.cs @@ -1,29 +1 @@ -// <copyright file="CallerArgumentExpressionAttribute.cs" company="Selenium Committers"> -// Licensed to the Software Freedom Conservancy (SFC) under one -// or more contributor license agreements. See the NOTICE file -// distributed with this work for additional information -// regarding copyright ownership. The SFC licenses this file -// to you under the Apache License, Version 2.0 (the -// "License"); you may not use this file except in compliance -// with the License. You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, -// software distributed under the License is distributed on an -// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY -// KIND, either express or implied. See the License for the -// specific language governing permissions and limitations -// under the License. -// </copyright> -namespace System.Runtime.CompilerServices; - -#if !NET8_0_OR_GREATER - -internal class CallerArgumentExpressionAttribute(string paramName) : Attribute -{ - public string ParamName = paramName; -} - -#endif The polyfill for ArgumentNullException.ThrowIfNull should be conditionally compiled using a preprocessor directive (e.g., #if !NET8_0_OR_GREATER). This prevents compilation errors on newer .NET frameworks that have a native implementation of this method. Examples: dotnet/src/webdriver/Internal/Polyfills/ArgumentNullExceptionExtensions.cs [1-38] // <copyright file="ArgumentNullExceptionExtensions.cs" company="Selenium Committers"> // Licensed to the Software Freedom Conservancy (SFC) under one // or more contributor license agreements. See the NOTICE file // distributed with this work for additional information // regarding copyright ownership. The SFC licenses this file // to you under the Apache License, Version 2.0 (the // "License"); you may not use this file except in compliance // with the License. You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 ... (clipped 28 lines) dotnet/src/webdriver/Internal/Polyfills/CallerArgumentExpressionAttribute.cs [22-29] #if !NET8_0_OR_GREATER internal class CallerArgumentExpressionAttribute(string paramName) : Attribute { public string ParamName = paramName; } #endif Solution Walkthrough: Before: // File: dotnet/src/webdriver/Internal/Polyfills/ArgumentNullExceptionExtensions.cs namespace System; internal static class ArgumentNullExceptionExtensions { extension(ArgumentNullException) { public static void ThrowIfNull([NotNull] object? arg, ...) { if (arg is null) { throw new ArgumentNullException(paramName); } } } } After: // File: dotnet/src/webdriver/Internal/Polyfills/ArgumentNullExceptionExtensions.cs #if !NET6_0_OR_GREATER // Or a similar TFM check like !NET8_0_OR_GREATER namespace System; internal static class ArgumentNullExceptionExtensions { extension(ArgumentNullException) { public static void ThrowIfNull([NotNull] object? arg, ...) { if (arg is null) { throw new ArgumentNullException(paramName); } } } } #endif Suggestion importance[1-10]: 9 __ Why: This suggestion correctly identifies a critical issue where the ThrowIfNull polyfill would conflict with the native implementation in newer .NET frameworks, likely causing build failures in a multi-targeted project.	High
Possible issue	✅ Correct the polyfill's conditional compilation Suggestion Impact: The commit removed the CallerArgumentExpressionAttribute polyfill file content entirely, which also avoids the duplicate-definition compilation issue the suggestion targeted, but it did not implement the specific preprocessor directive change. code diff: @@ -1,30 +1 @@ -// <copyright file="CallerArgumentExpressionAttribute.cs" company="Selenium Committers"> -// Licensed to the Software Freedom Conservancy (SFC) under one -// or more contributor license agreements. See the NOTICE file -// distributed with this work for additional information -// regarding copyright ownership. The SFC licenses this file -// to you under the Apache License, Version 2.0 (the -// "License"); you may not use this file except in compliance -// with the License. You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, -// software distributed under the License is distributed on an -// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY -// KIND, either express or implied. See the License for the -// specific language governing permissions and limitations -// under the License. -// </copyright> -namespace System.Runtime.CompilerServices; - -#if !NET8_0_OR_GREATER - -internal class CallerArgumentExpressionAttribute(string paramName) : Attribute -{ - public string ParamName = paramName; -} - -#endif - Correct the preprocessor directive for the CallerArgumentExpressionAttribute polyfill from #if !NET8_0_OR_GREATER to #if !NETCOREAPP3_0_OR_GREATER to avoid compilation errors on supported frameworks where the attribute is already defined. dotnet/src/webdriver/Internal/Polyfills/CallerArgumentExpressionAttribute.cs [22-29] -#if !NET8_0_OR_GREATER +#if !NETCOREAPP3_0_OR_GREATER -internal class CallerArgumentExpressionAttribute(string paramName) : Attribute +internal sealed class CallerArgumentExpressionAttribute(string paramName) : Attribute { public string ParamName = paramName; } #endif [Suggestion processed] Suggestion importance[1-10]: 9 __ Why: The suggestion correctly identifies a bug where the polyfill for CallerArgumentExpressionAttribute would cause compilation errors on .NET versions between .NET Core 3.0 and .NET 8, and provides the correct preprocessor directive to fix it.	High
Update

[nvborisenko]

Seems we need to explicitly specify:

• lang version 14 in csproj
• lang version in bazel build
• upgrade bazel rules for dotnet (requires bazel 8+)

[RenderMichael]

upgrade bazel rules for dotnet (requires bazel 8+)

Is that so? :(

I eagerly await it, for now this can sit in the drafts.

[nvborisenko]

Good news! Bazel is upgraded, so it supports .NET 10 SDK, meaning this PR is still alive.